Effects of acupuncture on RT-BM1 and maternal-fetal immune tolerance in rats with ovarian hyperstimulation

This study aimed to evaluate the effects of acupuncture on embryo implantation and maternal–fetal immune tolerance in rats with ovarian hyperstimulation, identify the mechanisms of acupuncture treatment, and promote application of acupuncture in the field of assisted reproduction. Eighty female Wistar rats were randomized into normal (N), model (M), acupuncture treatment (A), and progesterone treatment (P) groups, with 20 rats in each group. An ovarian hyperstimulation model was established in groups M, A, and P by the peritoneal injection of pregnant mare serum gonadotropin (PMSG) combined with human chorionic gonadotropin (HCG). Bilateral “Sanyinjiao (SP6)”, “Zusanli (ST36)” and “Taichong (LR3)” as acupoints were needled in rats in group A. Rats in group P received an intramuscular injection of progesterone (4 mg/kg). All pregnant rats were treated for seven days. On the 8th day, the pregnant rats were sacrificed for testing. The expression levels of estrogen (E2) and progesterone (P4) in serum and their receptors in the endometrium, Th1 and Th2 cytokines in serum and endometrium, RT-BM1 (the counterpart of HLA-G in rats) mRNA, Ly49 activating receptors (Ly49s3, Ly49s5) and inhibitory receptors (Ly49i3, Ly49i4, Ly49i5) on immunocytes in the maternal–fetal interface were detected using ELISA, Western blot, and real-time polymerase chain reaction (PCR). Compared with group N, the pregnancy rate and the number of implanted embryos were significantly decreased in group M (P < 0.05); E2 and P4 levels in serum, and the protein levels of ER-α and Progesterone Receptor (PGR) in the implantation site of endometrial tissue were significantly reduced in group M (P < 0.05); the expression of INF-γ and IL-2 in serum and endometrium were significantly increased, while the expression of IL-4, IL-6, and IL-10 in serum and endometrium were significantly decreased in group M(P < 0.05). The mRNA levels of RT-BM1, Ly49i3, and Ly49i4 receptors in group M were significantly higher than those in group N, whereas the mRNA levels of Ly49i5 and Ly49s5 receptors in group M were significantly lower than those in group N at the maternal–fetal interface (P < 0.05). The pregnancy rate and number of implanted embryos were significantly higher in group A than in group M (P < 0.05). Serum E2 and P4 levels were significantly higher in groups A and P than in group M (P < 0.05). The expression of ER-α and PGR in the implantation site of endometrial tissue in group A were significantly highe